<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <!--    视口，调整页面适应移动端
                width=device-width：页面宽度与设备宽度一致
                initial-scale=1：初始缩放为1，即不会缩放
                minimum-scale=1：最小缩放比
                maximum-scale=1：最大缩放比
                user-scalable=no：用户自定缩放
        -->
    <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
    <title>Title</title>
    <link href="bootstrap/css/bootstrap.css" rel="stylesheet">
    <style>
        .container {
            background-color: #00FFFF;
        }

        .row {
            background-color: red;
        }

        div {
            background-color: yellow;
            padding: 10px;
        }

        ul {
            background-color: black;
            height: 50px;
        }
        ul>li {
            background-color: red;
            margin: 10px;
            float: left;
            width: 300px;
        }
    </style>
    <!--    如下第三方库的JS一般写在head标签中-->
    <script src="js/jquery-3.5.1.js"></script>
    <script src="bootstrap/js/bootstrap.js"></script>
</head>
<body>
<div class="container-fluid">
    <div class="row">
        <div class="col-md-4 col-xs-1 col-sm-4 col-lg-4"></div>
    </div>
    <div class="row">
        <div class="col-xs-9">.col-xs-9</div>
        <div class="col-xs-3">.col-xs-4<br>Since 9 + 4 = 13 &gt; 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div>
        <div class="col-xs-6">.col-xs-6<br>Subsequent columns continue along the new line.</div>
    </div>

    <div class="row">
        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>

        <!-- Add the extra clearfix for only the required viewport -->
        <div class="clearfix visible-xs-block"></div>

        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
        <div class="col-xs-6 col-sm-3">.col-xs-6 .col-sm-3</div>
    </div>
<!--    <ul>-->
<!--        <li></li>-->
<!--        <li></li>-->
<!--        <li></li>-->
<!--        <li></li>-->
<!--    </ul>-->
    <div class="row">
        <div class="col-md-8 col-md-offset-2"></div>
    </div>
    <div class="row">
        <div class="col-xs-12 col-md-8">.col-xs-12 .col-md-8</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
    </div>
    <div class="row row-no-gutters">
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
        <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div>
    </div>
    <div class="row row-no-gutters">
        <div class="col-xs-6">.col-xs-6</div>
        <div class="col-xs-6">.col-xs-6</div>
    </div>
</div>
<script>
    // 变量污染

    // (function (){
    //     let JQuery;
    // })();
</script>
</body>
</html>